Schacter was born in Brownsville, Brooklyn and the youngest of 10 children. His parents came from Poland. His father, Pincus, was a seventh-generation shochet, or ritual slaughterer; his mother, the former Miriam Schimmelman, was a real estate manager.

During World War II, he was a chaplain in the Third Army's VIII Corps.[4] and was the first US Army Chaplain to enter and participate in the liberation of the Buchenwald concentration camp on April 11, 1945, barely an hour after it had been liberated by Gen. George Patton's troops. Rabbi Schacter remained at Buchenwald for months, tending to survivors and leading religious services. One of the children whom he personally rescued from the camp was then 7-year old Yisrael Meir Lau, who grew up to become the Ashkenazi Chief Rabbi of Israel. Later he aided in the resettlement of displaced persons, one of whom was teenaged Elie Wiesel, one of some thousand Jewish orphans liberated that day. He was discharged from the Army with the rank of captain.[5]

Schacter lived in the Riverdale, Bronx and died March 21, 2013. He was 95 and is survived by his wife, the former Pnina Gewirtz, whom he married in 1948; a son, Rabbi Jacob J. Schacter, the former director of the Soloveitchik Institute;[1] a daughter, Miriam Schacter; four grandchildren; and eight great-grandchildren.[7]